The purpose of the rollover detection system is activation of protection devices such as seat belts pretensioners, pop-up roll bars or air bags, especially air bags protecting occupants' heads during rollover accident.
In many systems for detecting dangerous situations, in particular in rollover detection systems there are two paths of signal processing: a main path being the main logic and an independent arming path, being a separate safety logic. An essential purpose of safety logic is to decrease the probability of inadvertent deployment in an event of failure or error in main rollover detection logic, wherein an activation signal of the main logic is summed with an activation signal of the safety logic by means of AND function at the last stage of processing, directly before an activation of protection devices.
Examples of logics of this kind are disclosed in U.S. Pat. Nos. 6,535,800, 6,600,414 or WIPO publication WO 03/010034. Publication WO 03/010034 discloses a rollover determination system comprising a first roll rate sensor, a lateral acceleration sensor and a main controller that determines, whether there is a possibility of rollover of the vehicle on the basis of the roll rate and lateral acceleration of the vehicle. The system comprises also a safety logic for confirming a rollover accident, whose output is summed with an output signal of a main rollover detection logic by means of AND gate.